Antimicrobial composition

ABSTRACT

An antimicrobial composition is provided that comprises about 10.0 to about 40.0 wt. % of one or more C1-8 alcohols, based on the total weight of the antimicrobial composition; and two or more of a surfactant; an enhancer; and a buffer. The pH of the composition is less than or equal to about 6.0 and the composition achieves a microbial log reduction of greater than 4.0 log CFU/ml at a contact time of 1 minute, in accordance ASTM E2783.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/132,696, filed on Sep. 17, 2018, which claims priority to and thebenefit of U.S. Application No. 62/559,221, filed on Sep. 15, 2017, theentire disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Antimicrobial compositions, sterilizers, disinfectants, and sanitizersare commercially important products and are widely used in personal,healthcare, and industrial settings, as well as in retail, food, andconsumer setting.

Disinfecting or sanitizing compositions have become increasingly popularfor providing antimicrobial effectiveness to the skin. Similarly,sanitizing or disinfecting compositions for hard surfaces, such ascountertops, walls, floors, etc., are also increasing in demand. Thesesanitizing or disinfecting compositions are often formulated asalcohol-based, and generally include greater than 50 wt. % of an alcoholand/or additional actives such as quaternary ammonium compounds.

It has generally been accepted that disinfecting and sanitizingcompositions require a high alcohol concentration to possess rapidantimicrobial activity. Typically, disinfecting and sanitizingcompositions with less than 40.0 wt. % alcohol are consideredineffective at killing germs rapidly, such as in an exposure period of10 minutes or less. Alcohol-based sanitizers, such as those comprisingethanol, typically have the additional advantage of rapid evaporationfrom the skin and other surfaces. However, skin treated with high levelsof alcohol may exhibit skin dryness and/or irritation.

Accordingly, sanitizing and disinfectant compositions having low alcoholconcentrations have been developed, while still providing rapidantimicrobial activity.

SUMMARY

Various exemplary embodiments of the subject invention are directed toan antimicrobial composition that includes about 10.0 to about 40.0 wt.% of one or more C₁₋₈ alcohols, based on the total weight of theantimicrobial composition, and two or more of a surfactant; an enhancer,and/or a buffer, wherein the pH of the antimicrobial composition is lessthan or equal to about 6.0. In various exemplary embodiments, theantimicrobial composition achieves a microbial log reduction of greaterthan 4.0 log CFU/mL at a contact time of 1 minute, in accordance withASTM E2783. In some exemplary embodiments, the C₁₋₈ alcohol is one ormore of methanol, ethanol, propanol, and mixtures thereof.

In some exemplary embodiments, the composition comprises between about12.0 and about 30.0 wt. % of the C₁₋₈ alcohol, based on the total weightof the antimicrobial composition.

In various exemplary embodiments, the buffer comprises an organic acidand salts thereof and is present in an amount from about 0.2 to about10.0 wt. %, based upon the total weight of the antimicrobialcomposition.

In some exemplary embodiments, the enhancer is one or more of anaromatic containing salt compound, an unsaturated organic acid or saltof an unsaturated organic acid compound, an aromatic organic acid,aromatic sulfate, saturated organic diol, organic aldehyde, and/or anaromatic alcohol. In various exemplary embodiments, the enhancer isselected from the group consisting of sorbic acid, sorbate compounds,benzoic acid, benzoate compounds, sulphur dioxide, sulphite compounds,natamycin, nitrate, nitrate compounds, salicylic acid, phenoxyethanol,thymol, cinnamaldehyde, methylparaben, propylparaben, sodium xylenesulfonate, 1,2 octane diol, 1,2 decane diol, and salts thereof. In someinstances, the enhancer is present in an amount from about 0.01 to about5.0 wt. %, based on the total weight of the antimicrobial composition.

In some exemplary embodiments, the surfactant is selected from the groupconsisting of non-ionic surfactants, anionic surfactants, and mixturesthereof. In some instances, the surfactant is a non-ionic surfactant,such as ethoxylated alcohol, alkyl polyglucoside, a polyalkoxylateddimethicone, or a combination thereof.

In accordance with further exemplary embodiments, an antimicrobialcomposition is provided that includes about 10.0 to about 40.0 wt. % ofone or more C₁₋₈ alcohols, based on the total weight of theantimicrobial composition; and two or more of a surfactant, a buffer,and an enhancer. The pH of the antimicrobial composition is less than orequal to about 6.0. In some exemplary embodiments, the antimicrobialcomposition results in no more than 15% of carriers positive within acontact time of no greater than 5 minutes in accordance with AOAC961.02.

In some exemplary embodiments, the composition comprises between about12.0 and about 30.0 wt. % of the C₁₋₈ alcohol, based on the total weightof the antimicrobial composition.

In various exemplary embodiments, the buffer comprises an organic acidand salts thereof and is present in an amount from about 0.2 to about10.0 wt. %, based upon the total weight of the antimicrobialcomposition.

In some exemplary embodiments, the enhancer is one or more of anaromatic containing salt compound, an unsaturated organic acid or saltof an unsaturated organic acid compound, an aromatic organic acid,aromatic sulfate, saturated organic diol, organic aldehyde, and/or anaromatic alcohol. In various exemplary embodiments, the enhancer isselected from the group consisting of sorbic acid, sorbate compounds,benzoic acid, benzoate compounds, sulphur dioxide, sulphite compounds,natamycin, nitrate, nitrate compounds, salicylic acid, phenoxyethanol,thymol, cinnamaldehyde, methylparaben, propylparaben, sodium xylenesulfonate, 1,2 octane diol, 1,2 decane diol, and salts thereof. In someinstances, the enhancer is present in an amount from about 0.01 to about5.0 wt. %, based on the total weight of the antimicrobial composition.

In some exemplary embodiments, the surfactant is selected from the groupconsisting of non-ionic surfactants, anionic surfactants, and mixturesthereof. In some instances, the surfactant is a non-ionic surfactant,such as ethoxylated alcohol, alkyl polyglucoside, a polyalkoxylateddimethicone, or a combination thereof.

In some exemplary embodiments, the antimicrobial composition is appliedto a wipe.

Further exemplary embodiments of the subject invention are directed toan antimicrobial composition that includes less than about 35.0 wt. % ofone or more C₁₋₈ alcohols, based on the total weight of theantimicrobial composition, and from about 0.50 to about 3.0 wt. % of twoor more of alkyl polyglucoside, a buffer, and an enhancer, wherein thepH of the antimicrobial composition is less than or equal to about 5.0.

In some exemplary embodiments, the composition comprises between about10.0 and about 30.0 wt. % of the C₁₋₈ alcohol, based on the total weightof the antimicrobial composition.

In various exemplary embodiments, the buffer comprises an organic acidand salts thereof and is present in an amount from about 0.2 to about3.0 wt. %, based upon the total weight of the antimicrobial composition.

In some exemplary embodiments, the enhancer is one or more of anaromatic containing salt compound, an unsaturated organic acid or saltof an unsaturated organic acid compound, an aromatic organic acid,aromatic sulfate, saturated organic diol, organic aldehyde, and/or anaromatic alcohol. In various exemplary embodiments, the enhancer isselected from the group consisting of sorbic acid, sorbate compounds,benzoic acid, benzoate compounds, sulphur dioxide, sulphite compounds,natamycin, nitrate, nitrate compounds, salicylic acid, phenoxyethanol,thymol, cinnamaldehyde, methylparaben, propylparaben, sodium xylenesulfonate, 1,2 octane diol, 1,2 decane diol, and salts thereof. In someinstances, the enhancer is present in an amount from about 0.01 to about5.0 wt. %, based on the total weight of the antimicrobial composition.

In some exemplary embodiments, the antimicrobial composition has a pH offrom about 1.5 to about 4.0.

Yet further exemplary embodiments of the present invention are directedto an antimicrobial composition comprising about 0.05 to about 5.0 wt. %of at least one surfactant; about 0.05 to about 5.0 wt. % of at leastone buffer; and about 0.01 to about 3.0 wt. % of at least one enhancer,wherein the pH of the antimicrobial composition is less than or equal toabout 5.0.

In some exemplary embodiments, the antimicrobial composition furtherincludes less than about 40.0 wt. % of one or more C₁₋₈ alcohols, basedon the total weight of the antimicrobial composition.

Yet further exemplary embodiments of the present invention are directedto a wipe comprising an antimicrobial composition comprising about 10.0to about 40.0 wt. % of one or more C₁₋₈ alcohols, based on the totalweight of the antimicrobial composition; and two or more of asurfactant, a buffer, and an enhancer. The pH of the antimicrobialcomposition is less than or equal to about 6.0 and the antimicrobialcomposition results in no more than 15% of carriers positive within acontact time of no greater than 5 minutes in accordance with AOAC961.02, modified for towelettes.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 graphically illustrates the efficacy of individual ingredientsagainst S. aureus compared to a full antimicrobial compositionformulated in accordance with the present inventive concepts.

FIG. 2 graphically illustrates the efficacy of individual ingredientsagainst S. aureus at a contact time of 30 seconds.

FIGS. 3 and 4 graphically illustrate the efficacy of variouscompositions against S. aureus at a contact time of 90 seconds.

DETAILED DESCRIPTION

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this application pertains. Although other methods andmaterials similar or equivalent to those described herein may be used inthe practice or testing of the exemplary embodiments, exemplary suitablemethods and materials are described below. In case of conflict, thepresent specification including definitions will control. In addition,the materials, methods, and examples are illustrative only and notintended to be limiting of the general inventive concepts.

The terminology as set forth herein is for description of the exemplaryembodiments only and should not be construed as limiting the applicationas a whole. Unless otherwise specified, “a,” “an,” “the,” and “at leastone” are used interchangeably. Furthermore, as used in the descriptionof the application and the appended claims, the singular forms “a,”“an,” and “the” are inclusive of their plural forms, unless contradictedby the context surrounding such.

Unless otherwise indicated, all numbers expressing quantities ofingredients, chemical and molecular properties, reaction conditions, andso forth used in the specification and claims are to be understood asbeing modified in all instances by the term “about.” The term “about”means within +/−10% of a value, or in some instances, within +/−5% of avalue, and in some instances within +/−1% of a value.

The general inventive concepts relate to an antimicrobial compositionthat contains a synergistic combination of alcohol and at least two ormore of a surfactant, an enhancer, and a buffer. The antimicrobialcomposition demonstrates rapid, broad spectrum activity againstmicroorganisms even at low levels of alcohol (such as at levels nogreater than 40 wt. % of the antimicrobial composition).

The physical form of the antimicrobial composition is not particularlylimited, and in one or more embodiments, the composition may bepresented as a liquid, such as one that is absorbed onto a wipe, poured,pumped, sprayed, or otherwise dispensed; a gel, an aerosol; or a foam,including both aerosol and non-aerosol foams. In one or moreembodiments, the antimicrobial composition may be presented on a wipe,i.e. a tissue or cloth that is wiped over a surface.

In some exemplary embodiments, the antimicrobial composition may beemployed on a wide variety of surfaces or substrates, including hardsurfaces, soft surfaces, animate surfaces (such as skin), non-living(inanimate) surfaces, soil, porous, and non-porous surfaces. In someexemplary embodiments, the antimicrobial composition is employed todisinfect or otherwise sanitize inanimate objects such as instruments,medical equipment, furniture, handrails, textiles, etc.

Some exemplary embodiments of the subject antimicrobial composition aredirected to skin applications and meet the requirements for Hand HygieneStandards Food and Drug Administration performance requirements whentested according to ASTM E2755, ASTM E1174, ASTM E2783, EuropeanStandard EN1500 and EN1499.

In some exemplary embodiments, the antimicrobial composition meets therequirements for sanitizing and disinfection as set forth by the EPA. Inone or more embodiments, the antimicrobial composition meets the EPArequirements for broad spectrum disinfection. In one or moreembodiments, the antimicrobial composition meets the requirements forhospital grade disinfection. In one or more embodiments, theantimicrobial composition meets the EPA requirements as a sanitizer(non-food contact) in accordance with ASTM E1153. In one or moreembodiments, the antimicrobial composition meets the EPA requirements asa sanitizer (food contact) in accordance with AOAC 960.09. In one ormore embodiments, the antimicrobial composition meets the EPArequirements as a disinfectant in accordance with AOAC 961.02.

In some exemplary embodiments, the antimicrobial composition comprisesan alcohol or combination of alcohols. By alcohol, it is meant anyorganic compound which has a hydroxyl functional group bonded to asaturated carbon atom. Alcohol has antimicrobial properties and has theability to kill many forms of bacteria, fungi, and viruses. In someembodiments, the alcohol is a C₁₋₈ alcohol, i.e. an alcohol containing 1to 8 carbon atoms. Such alcohols may be referred to as lower alkanols.Examples of lower alkanols include, but are not limited to, methanol,ethanol, propanol, butanol, pentanol, hexanol, and isomers and mixturesthereof. The alcohol may be either pure alcohol or denatured alcohol. Inone or more exemplary embodiments, the alcohol comprises ethanol,propanol, or butanol, or isomers or mixtures thereof. In one or moreexemplary embodiments, the alcohol comprises isopropanol. In otherexemplary embodiments, the alcohol comprises ethanol. In some exemplaryembodiments, the antimicrobial composition comprises a mixture ofalcohols. In one or more embodiments, the antimicrobial compositioncomprises a mixture of ethanol and isopropanol. In one or moreembodiments, the antimicrobial composition comprises a mixture ofisopropanol and n-propanol.

While C₁₋₈ alcohols are discussed herein, it is envisioned that longeralcohols (alcohols with more than 8 carbon atoms), or alcohols withvarious other functional groups would be similarly suitable. Forexample, in addition to the hydroxyl functional group, the alcohol mayfurther contain esters, carboxylic acids, ethers, amides, amines, alkylhalides, phenyls, as well as other carbonyl-containing functionalgroups.

In some exemplary embodiments, the antimicrobial composition comprisesat least about 1.0 wt. % C₁₋₈ alcohol, based on the total weight of theantimicrobial composition. In some exemplary embodiments, theantimicrobial composition comprises at least about 2.0 wt. % C₁₋₈alcohol, or at least about 3.0 wt. % C₁₋₈ alcohol, or at least about 5.0wt. % C₁₋₈ alcohol, or at least about 7.0 wt. % C₁₋₈ alcohol, or atleast about 10.0 wt. % C₁₋₈ alcohol, or at least about 12.0 wt. % C₁₋₈alcohol, or at least about 15.0 wt. % C₁₋₈ alcohol, or at least about20.0 wt. % C₁₋₈ alcohol, or at least about 25.0 wt. % C₁₋₈ alcohol, orat least about 30.0 wt. % C₁₋₈ alcohol, or at least about 35.0 wt. %C₁₋₈ alcohol, based on the total weight of the antimicrobialcomposition.

In some exemplary embodiments, the antimicrobial composition comprisesless than about 50.0 wt. % C₁₋₈ alcohol, based on the total weight ofthe antimicrobial composition. In some exemplary embodiments, theantimicrobial composition comprises less than about 45.0 wt. % C₁₋₈alcohol, or less than about 40.0 wt. % C₁₋₈ alcohol, or less than about35.0 wt. % C₁₋₈ alcohol, or less than about 30.0 wt. % C₁₋₈ alcohol, orless than about 25.0 wt. % C₁₋₈ alcohol, or less than about 20.0 wt. %C₁₋₈ alcohol, or less than about 15.0 wt. % C₁₋₈ alcohol, based on thetotal weight of the antimicrobial composition.

In some exemplary embodiments, the antimicrobial composition comprisesfrom about 3.0 to about 40.0 wt. % C₁₋₈ alcohol, or from about 5.0 to40.0 wt. % C₁₋₈ alcohol, or from about 7.0 to about 37.0 wt. % C₁₋₈alcohol, or from about 9.0 to about 35.0 wt. % C₁₋₈ alcohol, or fromabout 10.0 to about 32.0 wt. % C₁₋₈ alcohol, or from about 12.0 to about30.0 wt. % C₁₋₈ alcohol, or from about 15.0 to about 25.0 wt. % C₁₋₈alcohol, based on the total weight of the antimicrobial composition andincluding every narrower numerical range that falls within the broaderranges. In one exemplary embodiment, the antimicrobial compositioncomprises from about 15.0 to about 25.0 wt. % C₁₋₈ alcohol, based on thetotal weight of the antimicrobial composition. More or less alcohol maybe required in certain instances, depending particularly on otheringredients and/or the amounts thereof employed in the sanitizing ordisinfecting composition. However, surprisingly, it has further beendiscovered that increasing the amount of alcohol in the presentcomposition near 40 wt. % does not improve the antimicrobial efficacyand in fact, in some cases, causes the efficacy to decrease.

In some exemplary embodiments, the antimicrobial composition furthercomprises at least one surfactant. In some exemplary embodiments, thesurfactant is one or more of a nonionic, cationic, anionic, amphoteric,and zwitterionic surfactant. In some exemplary embodiments, theantimicrobial composition comprises a mixture of different surfactants.In some exemplary embodiments, the antimicrobial composition comprises amixture of different types of surfactants (e.g., one or more anionicsurfactants and one or more non-ionic surfactants). In other exemplaryembodiments, the antimicrobial composition comprises a mixture of thesame type of surfactants (e.g., a mixture of different non-ionicsurfactants). In another exemplary embodiment, the antimicrobialcomposition comprises a mixture of an anionic surfactant, a non-ionicsurfactant, and an amphoteric surfactant.

The amount of surfactant is not particularly limited, so long as it isat least an efficacy-enhancing amount. The minimum amount of surfactantthat corresponds to an efficacy-enhancing amount can be determined bycomparing the log kill of the target microbes that is achieved by acomposition comprising a select amount of alcohol to a compositioncomprising the same amount of alcohol and a given amount of surfactant.The amount of surfactant below which no difference in log kill is seenis an efficacy-enhancing amount.

In some exemplary embodiments, the surfactant is present in theantimicrobial composition in an amount from about 0.05 to about 15.0 wt.%, based on the total weight of the antimicrobial composition. In someexemplary embodiments, the surfactant is present in the antimicrobialcomposition in an amount from about 0.1 to about 10.0 wt. %, or fromabout 0.2 to about 5.0 wt. %, or from about 0.3 to about 2.5 wt. %, orfrom about 0.4 to about 2.0 wt. %, or from about 0.5 to about 1.5 wt. %,or from about 0.6 to about 0.8 wt. %, based on the total weight of theantimicrobial composition and including every narrower numerical rangethat falls within the broader ranges.

In some exemplary embodiments, the antimicrobial composition comprises adetersive amount of nonionic surfactant or a mixture of nonionicsurfactants.

In one or more embodiments, the nonionic surfactant includes ahydrophobic region, such as a long chain alkyl group or an alkylatedaryl group, and a hydrophilic group comprising an ethoxy and/or otherhydrophilic moieties. In one or more embodiments, the compositionfurther includes one or more nonionic foam-boosting co-surfactantshaving a hydrophobic region having an alkyl group containing six toeighteen carbon atoms, and an average of one to about twenty ethoxyand/or propoxy moieties. Examples of nonionic cleaning surfactantsinclude, but are not limited to, alkyl amine oxide, alkyl ether amineoxide, alkyl alcohol alkoxylates, aryl alcohol alkoxylates, substitutedalcohol alkoxylates, block nonionic copolymers, hetero nonioniccopolymers, alkanolamides, or polyethoxylated glycerol esters, andmixtures thereof.

In some exemplary embodiments, the nonionic surfactant is an alkylpolyglucoside. In some exemplary embodiments, the alkyl polyglucoside isderived from a glucose sugar and a fatty alcohol in which the alkylgroup contains 8-18 carbon atoms, glycerol fatty acid esters,polyoxyethylene glycerol fatty acid esters, polyoxyethylene sorbitanfatty acid esters, polyethyleneglycol fatty acid esters andpolyoxyethylene polyoxypropylene block copolymers with terminal hydroxylgroups and combinations thereof. In some exemplary embodiments, thenonionic surfactant is caprylyl/capryl glucoside.

Further exemplary nonionic surfactants include fatty alcohols such ascetyl alcohol, stearyl alcohol, cetostearyl alcohol, and oleyl alcohol,polyoxamers, ethoxylated fatty alcohols, such as PEG-80 sorbitanlaurate, polyoxyethylene glycol alkyl ethers, such as octaethyleneglycol monododecyl ether, and pentaethylene glycol monododecyl ether,polyoxypropylene glycol alkyl ethers, glucoside alkyl ethers,polyoxyethylene glycol octylphenol ethers, polyoxyethylene glycolalkylphenol ethers, such as nonoxynol-9, glycerol alkyl esters such asglyceryl laurate, polyoxyethylene glycol sorbitan alkyl esters, such aspolysorbate, sorbitan alkyl esters, cocamide MEA, cocamide DEA, amineoxides, such as dodecyldimethylamine oxide, block copolymers ofpolyethylene glycol and polypropylene glycol, such as poloxamers,polyethoxylated tallow amine, polyethylene glycol ethers, such astrideceth-9, and mixtures thereof.

Non-limiting examples of suitable nonionic surfactants are alsodisclosed in McCutcheon's Detergents and Emulsifiers, 1993 Annuals,published by McCutcheon Division, MC Publishing Co., Glen Rock, N.J.,pp. 1-246 and 266-273; in the CTFA International Cosmetic IngredientDictionary, Fourth Ed., Cosmetic, Toiletry and Fragrance Association,Washington, D.C. (1991) (hereinafter the CTFA Dictionary) at pages1-651; and in the CTFA Cosmetic Ingredient Handbook, First Ed.,Cosmetic, Toiletry and Fragrance Association, Washington, D.C. (1988)(hereafter the CTFA Handbook), at pages 86-94, each incorporated hereinby reference.

In one or more embodiments, the nonionic surfactant is alkylpolyglucoside, a polyalkoxylated dimethicone such as PEG-12 dimethicone,trideceth-9, or a combination thereof.

In some exemplary embodiments, the antimicrobial composition comprises acationic surfactant or a mixture of cationic surfactants. Surfactantsare classified as cationic if the charge on the hydrotrope portion ofthe molecule is positive. Surfactants in which the hydrotrope carries nocharge unless the pH is lowered close to neutrality or lower, but whichare then cationic (e.g. alkyl amines), are also included in this group.

In some exemplary embodiments, the cationic surfactant contains at leastone long carbon chain hydrophobic group and at least one positivelycharged nitrogen. The long carbon chain group may be attached directlyto the nitrogen atom by simple substitution; or more preferablyindirectly by a bridging functional group or groups in so-calledinterrupted alkylamines and amido amines. Such functional groups canmake the molecule more hydrophilic and/or more water dispersible, moreeasily water solubilized by co-surfactant mixtures, and/or watersoluble. For increased water solubility, additional primary, secondaryor tertiary amino groups can be introduced, or the amino nitrogen can bequaternized with low molecular weight alkyl groups. Further, thenitrogen can be a part of branched or straight chain moiety of varyingdegrees of unsaturation or of a saturated or unsaturated heterocyclicring. In addition, cationic surfactants may contain complex linkageshaving more than one cationic nitrogen atom. In one or more embodiments,the cationic surfactant is selected from alkylamines and their salts,alkyl imidazolines, ethoxylated amines quaternaries, such asalkylbenzyldimethylammonium salts, alkyl benzene salts, heterocyclicammonium salts, tetra alkylammonium salts, and the like, quaternizedpolysaccharides, alkyl polysaccharides, alkoxylated amines, alkoxylatedether amines, phospholipids, phospholipid derivatives, and mixturesthereof.

The surfactant compounds classified as amine oxides, amphoterics andzwitterions are themselves typically cationic in near neutral to acidicpH solutions and can overlap surfactant classifications.Polyoxyethylated cationic surfactants may behave like cationicsurfactants in acidic solution.

In some exemplary embodiments, the antimicrobial composition comprisesan anionic surfactant or a mixture of anionic surfactants. Exemplaryanionic surfactants include sulfates, such as sodium alkyl sulfate,sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium laurate,sodium lauryl sulfate (SLS) (also known as sodium dodecyl sulfate (SDS))and sodium laureth sulfate (SLES), sodium lauryl sarcosinate, potassiumlauryl sulfate, ammonium lauryl sulfate, ammonium laureth sulfate,ammonium xylene sulfonate, magnesium laureth sulfate, and sodium myrethsulfate; sulfonates, such as sodium nonanoyloxybenzenesulfonate;carboxylates; sulphated esters; sulphated alkanolamides; alkylphenols;and mixtures thereof. In other exemplary embodiments, the antimicrobialcomposition comprises an amphoteric surfactant. Amphoteric surfactants,sometimes referred to as ampholytic surfactants, may contain both abasic and an acidic hydrophilic group and an organic hydrophobic group.These ionic entities may be any of the anionic or cationic groupsdescribed herein for other types of surfactants. A basic nitrogen and anacidic carboxylate group are the typical functional groups employed asthe basic and acidic hydrophilic groups. In a few surfactants,sulfonate, sulfate, phosphonate or phosphate provide the negativecharge.

Amphoteric surfactants can be broadly described as derivatives ofaliphatic secondary and tertiary amines, in which the aliphatic radicalmay be straight chain or branched and wherein one of the aliphaticsubstituents contains from 8 to 18 carbon atoms and one contains ananionic water solubilizing group, e.g., carboxy, sulfo, sulfato,phosphato, or phosphono. Amphoteric surfactants include acyl/dialkylethylenediamine derivatives (e.g., 2-alkyl hydroxyethyl imidazolinederivatives) and their salts, and N-alkylamino acids and their salts.Specific examples include 2-alkyl hydroxyethyl imidazoline,cocoamphopropionate, cocoamphocarboxy-propionate, cocoamphoglycinate,cocoamphocarboxy-glycinate, cocoamphopropyl-sulfonate, andcocoamphocarboxy-propionic acid.

Amphoteric surfactants include those derived from coconut products suchas coconut oil or coconut fatty acid, including alkyl amphodicarboxylicacid. A specific example of an amphoteric surfactant, disodium cocoamphodipropionate, is commercially available under the tradename Miranol™ FBSfrom Rhodia Inc., Cranbury, N.J. Another coconut-derived amphotericsurfactant with the chemical name disodium cocoampho diacetate is soldunder the tradename Miranol C2M-SF Conc., also from Rhodia Inc.,Cranbury, N.J.

A typical listing of amphoteric classes, and species of thesesurfactants, is given in U.S. Pat. No. 3,929,678, which is incorporatedby reference herein. In some exemplary embodiments, the amphotericsurfactant is an amine oxide. Non-limiting examples of suitable amineoxide compounds include 1-Dodecanamine, N,N-dimethyl-, N-oxide;1-Tetradecanamine, N,N-dimethyl-, N-oxide; Amines, C10-16-alkyldimethyl,N-oxides; Amines, C12-18-alkyldimethyl, N-oxides; Decanamine,N,N-dimethyl-, N-oxide; Hexadecanamine, N,N-dimethyl-, N-oxide;Octadecanamine, N,N-dimethyl-, N-oxide; Amine oxides, cocoalkyldimethyl;Amines, C10-18-alkyldimethyl, N-oxides; Amines, C12-16-alkyldimethyl,N-oxides; Ethanol, 2,2′-iminobis-, N-coco alkyl derivs., N-oxides;Ethanol, 2,2′-(dodecyloxidoimino)bis-; Ethanol,2,2′-(octadecyloxidoimino)bis-; Ethanol, 2,2′-iminobis-, N-tallow alkylderivs., N-oxides; Ethanol,2,2′-[(9Z)-9-octadecenyloxidoimino]bis-ethanol N-oxide. In someexemplary embodiments, the amine oxide is lauramine oxide.

In some exemplary embodiments, the amphoteric surfactant is azwitterionic surfactant. Typically, a zwitterionic surfactant includes apositive charged quaternary ammonium or, in some cases, a sulfonium orphosphonium ion, a negative charged carboxyl group, and an alkyl group.Zwitterionic surfactants generally contain cationic and anionic groupswhich ionize to a nearly equal degree in the isoelectric region of themolecule and which can develop strong “inner-salt” attraction betweenpositive-negative charge centers. Non-limiting examples of suchzwitterionic synthetic surfactants include derivatives of aliphaticquaternary ammonium, phosphonium, and sulfonium compounds, in which thealiphatic radicals can be straight chain or branched, and wherein one ofthe aliphatic substituents contains from 8 to 18 carbon atoms and onecontains an anionic water solubilizing group, e.g., carboxy, sulfonate,sulfate, phosphate, or phosphonate. In some exemplary embodiments, thezwitterionic surfactant is a betaine surfactant, a sultaine surfactant,or a combination thereof. In some exemplary embodiments, thezwitterionic surfactant is a betaine surfactant. In some exemplaryembodiments, the zwitterionic surfactant is cocamidopropyl betaine.

In some exemplary embodiments, the antimicrobial composition comprises abuffer (pH-adjuster), such as an acid, to help achieve the pH rangesdisclosed herein. In some exemplary embodiments, the acid is an organicacid. In other exemplary embodiments, the buffer is a mixture of anorganic acid and an inorganic acid (mineral acid). In some exemplaryembodiments, the buffer may comprise a basic (or alkaline) buffer toraise the pH to a more basic level. The basic buffer may comprise a weakbase and one of its salts, such as a mixture of ammonia and ammoniumchloride.

In some exemplary embodiments, the organic acid has one or morecarboxylic acid groups. In other exemplary embodiments, the organic acidcontains one or more thiol groups, enol groups, phenol groups, sulfonicgroups, or combinations thereof. In some exemplary embodiments, theorganic acid is one or more of citric acid, lactic acid, formic acid,acetic acid, propionic acid, butyric acid, caproic acid, oxalic acid,maleic acid, benzoic acid, malic acid, valeric acid, carbonic acid, uricacid, and the like, and the salts thereof. The organic acid can besubstituted or un-substituted.

Non-limiting examples of other suitable organic acids include adipicacid, benzene 1,3,5 tricarboxylic acid, chlorosuccinic acid, cholinechloride, cis-aconitic acid, citramalic acid, cyclobutane 1,1,3,3tetracarboxylic acid, cyclohexane 1,2,4,5 tetracarboxylic acid,cyclopentane 1,2,3,4 tetracarboxylic acid, diglycolic acid, fumaricacid, glutamic acid, glutaric acid, glyoxylic acid, isocitric acid,ketomalonic acid, malonic acid, nitrilotriacetic acid, oxalacetic acid,oxalic acid, phytic acid, p-toluenesulfonic acid, salicylic acid,succinic acid, tartaric acid, tartronic acid, tetrahydrofuran 2,3,4,5tetracarboxylic acid, tricarballylic acid, versene acids,3-hydroxyglutaric acid, 2-hydroxypropane 1,3 dicarboxylic acid, glycericacid, furan 2,5 dicarboxylic acid, 3,4-dihydroxyfuran-2,5 dicarboxylicacid, 3,4-dihydroxytetrahydrofuran-2,5-dicarboxylic acid, 2-oxo-glutaricacid, dl-glyceric acid, 2,5 furandicarboxylic acid, and the saltsthereof.

In some exemplary embodiments, the buffer includes an inorganic acid. Insome exemplary embodiments, the inorganic acid is one or more of aphosphorus-based compound, a sulfur-based compound, or a nitrogen-basedcompound. Non-limiting examples of suitable inorganic acids includehydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boricacid, hydrofluoric acid, hydrobromic acid, perchloric acid, bromousacid, iodous acid, and hydroiodic acid. In some embodiments, the acidcomprises sulfuric acid. In some exemplary embodiments, the buffer has apH (under standard conditions; 1 mmol/L) of less than about 4.0, or lessthan about 3.5, or less than about 3.0, or less than about 2.9, or lessthan about 2.8.

In some exemplary embodiments, the total amount of buffer is present inan amount from about 0.1 to about 15.0 wt. %, based upon the totalweight of the antimicrobial composition. In some exemplary embodiments,the total amount of buffer is present in an amount from about 0.2 toabout 10.0 wt. %, or from about 0.3 to about 5.0 wt. %, or from about0.31 to about 3.0 wt. %, or from about 0.4 to about 2.5 wt. %, or fromabout 0.5 to about 2.0 wt. %, based upon the total weight of theantimicrobial composition and including every narrower numerical rangethat falls within the broader ranges.

It has been found that certain acids enhance the antimicrobial efficacyof the compositions, beyond their traditional effect of simply adjustingthe pH of the composition. In some exemplary embodiments, acidifying theantimicrobial composition enhances the efficacy of the compositions,such that the efficacy is equivalent to, or greater than, compositionscontaining much higher amounts of alcohol.

In some exemplary embodiments, the antimicrobial composition furthercomprises an enhancer. As used herein, the term enhancer means acomponent that contributes to the overall efficacy of the compositionbut does not itself have rapid antimicrobial activity (e.g. an exposuretime of less than 10 minutes). In some exemplary embodiments, theenhancer is one or more of an aromatic containing salt compound, anunsaturated organic acid or salt of an unsaturated organic acidcompound, an aromatic organic acid, aromatic sulfate, saturated organicdiol, organic aldehyde and/or an aromatic alcohol. Non-limiting examplesof suitable enhancers include sorbic acid, sorbate compounds, benzoicacid, benzoate compounds, sulphur dioxide, sulphite compounds,natamycin, nitrate, nitrate compounds, thymol, cinnamaldehyde,methylparaben, propylparaben, sodium xylene sulfonate, 1,2 octane diol,1,2 decane diol, and salts thereof. Such salts include, for example,benzoates, sorbates, sulphates, sodium benzoate, sodium sorbate,potassium sorbate, calcium sorbate, and the like. In some exemplaryembodiments, the enhancer is listed on the EPA's Minimal Risk Inerts orIngredients for Use in Food-Contact Surface Sanitizing Solutions. Insome exemplary embodiments, the enhancer is a benzoate such as sodiumbenzoate.

In some exemplary embodiments, the enhancer is added in theantimicrobial composition in an amount less than about 10.0 wt. %, orless than about 5.0 wt. %, or less than about 2.5 wt. %, or less thanabout 1.5 wt. %, or less than about 1.0 wt. %, or less than about 0.75wt. %, or less than about 0.5 wt. %, based on the total weight of theantimicrobial composition. In some exemplary embodiments, the enhanceris added from about 0.01 to about 5.0 wt. %, or from about 0.05 to about3.0 wt. %, or from about 0.1 to about 2.0 wt. %, or from about 0.2 toabout 1.0 wt. %, based on the total weight of the antimicrobialcomposition and including every narrower numerical range that fallswithin the broader ranges.

In some exemplary embodiments, the pH of the antimicrobial compositionis less than about 6.0, or less than about 5.5, or less than about 5.0,or less than about 4.5. In some exemplary embodiments, the pH of theantimicrobial composition is from about 1.5 to about 6.0. In some otherexemplary embodiments, the pH of the antimicrobial composition fromabout 2.0 to about 5.5, or from about 2.5 to about 5.0, or from about3.0 to about 4.5.

Advantageously, a synergistic antimicrobial effect is observed even whenthe composition includes no more than 40 wt. % alcohol at an acidic pH.Typically, disinfecting and sanitizing compositions with less than 40.0wt. % alcohol are considered ineffective at killing germs rapidly, suchas in an exposure period of 10 minutes or less. It has surprisingly beenfound, however, that while compositions containing 40.0 wt. % or less ofalcohol typically show insufficient antimicrobial efficacy, theantimicrobial composition described herein having a maximum of 40 wt. %alcohol at an acidic pH exhibits enhanced antimicrobial efficacy in arapid time frame, such as within an exposure period of 10 minutes orless. In some exemplary embodiments, alcohol concentrations that exhibitlittle or no efficacy on their own provide an enhanced efficacy whensynergistically combined with the ingredients described herein, even atalcohol concentrations that are no more than about 40.0 wt. %, or nomore than about 35.0 wt. %, or no more than about 30.0 wt. %, or no morethan about 25.0 wt. %, and a further enhanced efficacy when the pH ofthe antimicrobial composition is less than about 6.0 or less than about5.0.

Moreover, a further synergistic antimicrobial effect is observed whenthe antimicrobial composition comprises at least one of a buffer and anenhancer, collectively at a concentration of at least 0.50 wt. %, basedon the total weight of the antimicrobial composition, at an acidic pH ofno greater than 6. In some exemplary embodiments the concentration ofbuffer and/or enhancer is collectively at least 0.75 wt. %, based on thetotal weight of the antimicrobial composition. In various exemplaryembodiments, the concentration of buffer and/or enhancer is collectivelybetween 0.50 and 4.0 wt. %, or between 1.0 and 3.0 wt. %, based on thetotal weight of the antimicrobial composition. A particularlyadvantageous antimicrobial effect is observed when the buffer is anorganic acid, such as citric acid, the enhancer is the salt of anaromatic acid, such as sodium benzoate, and the pH of the composition isless than 6.

The antimicrobial composition may comprise additional ingredients thatdo not deleteriously affect the synergistic composition disclosed above.For instance, in some exemplary embodiments, the antimicrobialcomposition may include one or more chelating agents. The chelatingagent is not particularly limited and can include any central atom withtwo or more coordinate bonds between a polydentate ligand. Both organicand inorganic chelating agents can be used in the antimicrobialcomposition. In some exemplary embodiments, the chelating agentcomprises one or more of ethylenediamine, ethylenediaminetetraaceticacid (EDTA) and its salts, ethylenediamine-N,N′-disuccinic acid (EDDS),diethylenetriaminepentaacetic acid, N,N-bis(carboxymethyl)glycine,salicylic acid, polyphosphates, ascorbic acid. In some exemplaryembodiments, the chelating agent is EDTA. In some exemplary embodiments,the chelating agent comprises one or more amino acid-based chelant, suchas, for example, methylgycine diacetic acid.

In some exemplary embodiments, the chelating agent is added in theantimicrobial composition in an amount up to about 10.0 wt. %, or up toabout 5.0 wt. %, or up to about 2.5 wt. %, or up to about 1.5 wt. %, orup to about 1.0 wt. %, or up to about 0.75 wt. %, or up to about 0.5 wt.%, based on the total weight of the antimicrobial composition. In someexemplary embodiments, the chelating agent is included in an amount ofat least about 0.001 wt. %, or at least about 0.01 wt. %, or at leastabout 0.05 wt. %, or at least about 0.1 wt. %, or at least about 0.5 wt.%, or at least about 0.7 wt. %, based on the weight of the antimicrobialcomposition. In some exemplary embodiments the chelating agent is addedfrom about 0.001 to about 2.0 wt. %, or from about 0.005 to about 1.5wt. %, or from about 0.05 to about 1.0 wt. %, or from about 0.1 to about0.8 wt. %, based on the total weight of the antimicrobial composition.

In some exemplary embodiments, the antimicrobial composition issubstantially free of, or completely free of fatty acids as well as anysalts or derivatives thereof. By “essentially free” it is meant that theantimicrobial composition contains no greater than 5.0 wt. %, preferablyno greater than 1.0 wt. %, and more preferably no greater than 0.5 wt. %of the specified compound.

In some exemplary embodiments, the antimicrobial composition furthercomprises a fragrance. Any scent may be used in the antimicrobialcomposition including, but not limited to, any scent classification on astandard fragrance chart, such as floral, oriental, woody, and fresh.Exemplary scents include cinnamon, clove, lavender, peppermint,rosemary, thyme, lemon, citrus, coconut, apricot, plum, watermelon,ginger, cranberry, and combinations thereof. In some exemplaryembodiments, the fragrance is composed of ingredients listed on theEPA's minimal risk inerts or ingredients for use in food-contact surfacesanitizing solutions.

In some exemplary embodiments, the fragrance is included in theantimicrobial composition in an amount from about 0.005 wt. % to about5.0 wt. %, in other embodiments, from about 0.01 wt. % to about 3.0 wt.%, and in other embodiments, from about 0.05 wt. % to about 1.0 wt. %,or about 0.1 to 0.5 wt. %, based on the total weight of theantimicrobial composition. The fragrance can be made of any perfume,essential oil, aroma compounds, fixatives, terpenes, solvents, and thelike. In some exemplary embodiments, the essential oils may include, forexample, one or more of Limonene, Citrus Aurantium Dulcis (Orange) PeelOil, Eucalyptus globulus Leaf Oil, Citrus grandis (Grapefruit) Peel Oil,Linalool, Litsea cubeba Fruit Oil, Lavandula hybrida Oil, Abies sibiricaOil, Mentha citrata Leaf Extract, Coriandrum sativum (Coriander) FruitOil, Piper nigrum (Pepper) Fruit Oil, and Canarium luzonicum GumNonvolatiles.

In some exemplary embodiments, the antimicrobial composition comprisesone or more carriers. The carrier can be any suitable compound able toeffectively deliver and/or transport the antimicrobial composition. Insome exemplary embodiments, the carrier is water or a base cleaner.Other carriers, such as saline, inorganic salt solutions, fatty esters,ethers, amides, acetates, silicones, triglycerides, and varioushydrocarbons. In other exemplary embodiments, the antimicrobialcomposition does not include any carrier and is delivered as aconcentrate.

In some exemplary embodiments, the antimicrobial composition includeswater as the carrier. In some exemplary embodiments, the antimicrobialcomposition comprises at least about 1.0 wt. % of a carrier, or at leastabout 10.0 wt. % of a carrier, or at least about 20.0 wt. % of acarrier, or at least about 30.0 wt. % of a carrier, or at least about35.0 wt. % of a carrier, or at least about 40.0 wt. % of a carrier, orat least about 50.0 wt. % of a carrier, or at least about 60.0 wt. % ofa carrier, or at least about 70.0 wt. % of a carrier, or at least about80.0 wt. % of a carrier, or at least about 85.0 wt. % of a carrier,based on the total weight of the antimicrobial composition. In someexemplary embodiments, the antimicrobial composition comprises fromabout 50.0 wt. % to about 85.0 wt. % of a carrier, or from about 55.0 toabout 80.0 wt. % of a carrier, or from about 60.0 to about 75.0 wt. % ofa carrier, based on the total weight of the antimicrobial compositionand including every narrower numerical range that falls within thebroader ranges. More or less of a carrier may be required in certaininstances, depending particularly on other ingredients and/or theamounts thereof employed in the antimicrobial composition.

A wide variety of non-limiting cosmetic and pharmaceutical ingredientscommonly used in the skin care industry may additionally be suitable foruse in the compositions of the present invention. Examples of theseingredients include: abrasives, anti-acne agents, anticaking agents,antioxidants, binders, biological additives, bulking agents, chelatingagents, chemical additives; colorants, cosmetic astringents, cosmeticbiocides, denaturants, drug astringents, emulsifiers, externalanalgesics, film formers, foam surfactants, humectants, opacifyingagents, plasticizers, preservatives (sometimes referred to asantimicrobials), propellants, reducing agents, skin bleaching agents,skin-conditioning agents (emollient, miscellaneous, and occlusive), skinprotectants, solvents, surfactants, foam boosters, hydrotropes,solubilizing agents, suspending agents (nonsurfactant), sunscreenagents, ultraviolet light absorbers, detackifiers, and viscosityincreasing agents (aqueous and nonaqueous). Examples of other functionalclasses of materials useful herein that are well known to one ofordinary skill in the art include solubilizing agents, sequestrants,keratolytics, topical active ingredients, and the like.

Advantageously, auxiliary antimicrobials, some of which can be harsh onsurfaces, are not required. In some exemplary embodiments, theantimicrobial composition does not contain any auxiliary antimicrobialingredients. Any antimicrobial ingredient other than the combination ofalcohol, surfactant, enhancer, and buffer may be referred to as anauxiliary antimicrobial agent. In one embodiment, the amount ofauxiliary antimicrobial agent is less than about 1.0 wt. %, or less thanabout 0.5 wt. %, or less than about 0.25 wt. %, or less than about 0.1wt. %, or less than about 0.05 wt. %, or less than about 0.01 wt. %,based on the total weight of the antimicrobial composition. In someexemplary embodiments, the antimicrobial composition is devoid ofauxiliary antimicrobial agents.

Advantageously, certain ingredients that have been designated ascritical to current food contact surface cleaners can be limited in theantimicrobial composition of the present invention. Many of thesecompounds have deleterious side effects that make them undesirable foruse in a disinfectant.

In some exemplary embodiments, the amount of hypochlorous acid andprecursors thereof, in the antimicrobial composition is limited. In someexemplary embodiments, the amount of hypochlorous acid and precursorsthereof, in the antimicrobial composition is less than about 0.5 wt. %,or less than about 0.1 wt. %, based on the total weight of theantimicrobial composition. In some exemplary embodiments, theantimicrobial composition is devoid of hypochlorous acid.

In some exemplary embodiments, the amount of peroxyacids, such asperacetic acid, in the antimicrobial composition may be limited. In someexemplary embodiments, the amount of peroxyacid in the antimicrobialcomposition is less than 0.5 wt. %, or less than about 0.1 wt. %, basedon the total weight of the antimicrobial composition. In anotherembodiment, the antimicrobial composition is devoid of peroxyacid.

In some exemplary embodiments, the amount of peroxide, such as hydrogenperoxide, in the antimicrobial composition, is limited. In someexemplary embodiments, the amount of peroxide in the antimicrobialcomposition is less than about 0.5 wt. %, or less than about 0.1 wt. %,based on the total weight of the antimicrobial composition. In someexemplary embodiments, the antimicrobial composition is devoid ofperoxide.

In some exemplary embodiments, the amount of quaternary compounds in theantimicrobial composition is limited or completely excluded. Quaternarycompounds are compounds that include a positively charged polyatomic ionof the structure NR⁴⁺, R being an alkyl group or an aryl group. Unlikethe ammonium ion (NH⁴⁺) and the primary, secondary, or tertiary ammoniumcations, the quaternary ammonium cations are permanently charged,independent of the pH of their solution. Examples are benzalkoniumchloride, benzethonium chloride, methylbenzethonium chloride,cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide,dofanium chloride, tetraethylammonium bromide, didecyldimethylammoniumchloride and domiphen bromide. In some exemplary embodiments, the amountof quaternary compounds in the antimicrobial composition is less thanabout 0.5 wt. %, or less than about 0.1 wt. %, based on the total weightof the antimicrobial composition. In some exemplary embodiments, theantimicrobial composition is devoid of quaternary compounds.

It is believed that the microstructure of the composition influences theinteraction between the composition and surfaces of microorganisms,enhancing the composition's disinfecting ability. The alcohol, enhancer,and buffer combine to influence the micelle structure created by thesurfactant. Improved disinfection efficiency reaches a maximum informulas with less than 40 wt. % alcohol, which indicates the formationof micelles with maximum efficiency for interacting with microorganismsin this region. Due to this reason, increased levels of alcohol actuallyinhibit the disinfection ability of the formula.

Indeed, any component other than the alcohol, surfactant, enhancer, andbuffer is not necessary to achieve the antimicrobial efficacy of thepresent antimicrobial composition, when combined at a pH below 6 and canoptionally be limited to less than about 5.0 wt. %, or less than about2.0 wt. %, or less than about 1.0 wt. %, or less than about 0.5 wt. %,or to less than about 0.1 wt. %, or to less than about 0.01 wt. %, or toless than about 0.001 wt. %, based on the total weight of theantimicrobial composition. In some exemplary embodiments, theantimicrobial composition is devoid of any component other than alcohol,surfactant, buffer, enhancer, chelating agent, and optionally water orother suitable carrier.

In some exemplary embodiments, the antimicrobial composition comprisesless than about 40.0 wt. % of one or more C₁₋₈ alcohols, one or moresurfactants, an enhancer, and a buffer, and has a pH no higher than 6.In some exemplary embodiments, the antimicrobial composition comprisesless than about 40.0 wt. % of one or more C₁₋₈ alcohols, one or morenonionic surfactants, and a combined concentration of a buffer and anenhancer of at least 0.50 wt. %. In some exemplary embodiments, theantimicrobial composition comprises less than about 40.0 wt. % ofethanol, a nonionic surfactant, sodium benzoate, and citric acid. Insome exemplary embodiments, the antimicrobial composition comprises lessthan about 40.0 wt. % of ethanol, caprylyl/capryl glucoside, and citricacid. In some exemplary embodiments, the antimicrobial compositioncomprises less than about 40.0 wt. % of ethanol, caprylyl/caprylglucoside, an enhancer, citric acid, and an inorganic acid. In someexemplary embodiments, the antimicrobial composition includes less thanabout 30 wt. % ethanol, 0.1-1.0 wt. % caprylyl/capryl glucoside, acombined concentration of citric acid and sodium benzoate of 0.75-4.0wt. %, and 0.01-0.1 wt. % sulfuric acid. In some exemplary embodiments,the antimicrobial composition comprises one or more nonionicsurfactants, a combined concentration of a buffer and an enhancer of atleast 0.50 wt. %, and optionally alcohol.

In some exemplary embodiments, the antimicrobial composition is utilizedin a premoistened wipe. Generally, the premoistened wipe comprises acomposition and a substrate. In some exemplary embodiments, the wipesubstrate is selected to tightly hold the antimicrobial compositionduring preparation and storage, and also readily express the liquidduring use.

In some exemplary embodiments, the premoistened wipe includes asubstrate comprising a woven or nonwoven web of natural fibers,synthetic fibers, or mixtures of natural and synthetic fibers. Suitablenatural fibers include but are not limited to cellulosic fibers, such aswood pulp fibers, cotton, and rayon. Suitable synthetic fibers includefibers commonly used in textiles, including but not limited to polyesterand polypropylene fibers.

Various forming methods can be used to form a suitable fibrous web. Insome exemplary embodiments, the web can be made by nonwoven dry formingtechniques, such as air-laying, or alternatively by wet laying, such ason a papermaking machine. Other nonwoven manufacturing techniques,including but not limited to techniques such as meltblown, spunbond,needle punch, and hydroentanglement (i.e., spunlace) methods, may alsobe used.

Unexpectedly, when a surfactant is combined with less than about 40.0wt. % of a C₁₋₈ alcohol at a low pH, with a buffer and an enhancer, suchas those disclosed herein, antimicrobial activity is synergisticallyenhanced, which is more than just an additive effect. In some exemplaryembodiments, the antimicrobial composition is effective in killing gramnegative and gram positive bacteria, fungi, parasites, non-enveloped andenveloped viruses. In some exemplary embodiments, the antimicrobialcomposition has rapid antimicrobial efficacy against bacteria such asStaphylococcus aureus, methicillin-resistant S. aureus, Escherichiacoli, Pseudomonas aeruginosa, Serratia marcescens, Mycobacterium bovis,Salmonella enterica, viruses such as Adenovirus, Feline Calicivirus,Hepatitis C, and Rotavirus, fungi such as Candida albicans, Trichophytoninterdigitale, and Aspergillus niger, and black mold spores Stachybotryschartani.

EXAMPLES

Examples 1-3 set forth various antimicrobial compositions applied towipes and tested to determine their effectiveness on hard non-porous,inanimate environmental surfaces according to the AOAC 961.02 method,modified for towelettes. Test cultures of S. aureus were used to testeach disinfectant's efficacy. Results are expressed as a fraction ofcarriers that exhibited growth e.g. percent positive carriers.

Example 1

Eleven compositions were prepared and tested under the method describedabove with a contact time of 90 seconds to determine their effectivenessas a biocide. Carriers inoculated with Staphylococcus aureus were testedfor each of the compositions in Table 1. Table 1 shows the results ofthe tests that were performed on various compositions.

TABLE 1 Non-ionic Total Percent Composition Ethanol surfactant EnhancerBuffer pH Positive 1a 20.00% 0.500% 0.1000% 1.500% 3.0 5% 1b 30.00%0.500% 0.1000% 1.500% 3.0 18%  2a 20.00% 2.000% 0.1000% 1.500% 3.0 9% 2b30.00% 2.000% 0.1000% 1.500% 3.0 10%  3a 20.00% 2.000% 1.0000% 1.500%3.0 3% 3b 30.00% 2.000% 1.0000% 1.500% 3.0 10%  4a 20.00% 0.500% 1.1000%1.500% 3.0 9% 4b 30.00% 0.500% 1.1000% 1.500% 3.0 15%  5a 20.00% 0.500%2.0000% 1.500% 3.0 0% 5b 30.00% 0.500% 2.0000% 1.500% 3.0 8% 6  25.00%1.250% 1.500% 1.500% 3.0 3%

In Table 1 above, pairs of substantially identical formulations otherthan varied ethanol levels were tested. Ethanol is typically active onits own at concentrations from 50-90 wt. %. Typically, an increase inethanol will result in an increase in antimicrobial efficacy. However,in Compositions 1 a/b, 3 a/b, 4 a/b and 5 a/b, the efficacy of thecompositions was higher at 20% ethanol when compared to 30% ethanol(lower percent positive carriers). For Compositions 2 a/b, the level ofefficacy held consistent even when ethanol concentration increased.Compositions 3a, 5a, and 6 were the most efficacious formulas andcontained 20%, 20% and 25% ethanol, respectively. This data issurprising, based on the accepted assumption that alcohol increasesefficacy. Such an assumption does not appear to always hold true in thiscompositional space.

Example 2

Four compositions comprising only ethanol, a pH adjuster, and water atvarious pH levels were prepared and tested under the AOAC 961.02 method,modified for towelettes to determine the antimicrobial effectiveness ofethanol alone. Carriers inoculated with Staphylococcus aureus weretested using each of the compositions in Table 2. The amount of carrierspositive after a contact time of 120 seconds was calculated andreflected below in Table 2.

TABLE 2 Non-ionic Chelating Percent Comp. Ethanol Surfactant EnhancerBuffer Agent pH Final Positive 7 25.00 wt. % 0 0 0 0 not measured   100%8 40.00 wt. % 0 0 0 0 5.0 96.67% 9 50.00 wt. % 0 0 0 0 3.29 30.00% 1050.00 wt. % 0 0 0 0 3.00 73.30%

Table 2 illustrates that a composition having only 25% ethanol did notdemonstrate any efficacy against S. aureus. See Composition 7. Moreover,at a pH of 5, an ethanol concentration of 40.00 wt. % demonstrated anefficacy of about 96.67% positive carriers. Only at an ethanolconcentration of 50.00 wt. %, along with a pH of 3.29, did the efficacybegin to fall below 50% positive carriers, which is still above themaximum of 15% positive carriers set forth in the present application.

Example 3

A sample with 25.0 wt. % ethanol, 0.62 wt. % decyl glucoside, 0.5 wt. %sodium benzoate, 0.75 wt. % citric acid, and the balance water (“SampleA”) was tested according to the methods described above to determine itsrapid antimicrobial efficacy. The pH of the composition was 4.0. Table 3details the results of the efficacy trials of Sample A over 2 minutes. Asample with 20.0 wt. % ethanol, 0.50 wt. % decyl glucoside, 0.10 wt. %sodium benzoate, 1.50 wt. % citric acid, and the balance water (“SampleB”) was tested according to the methods described above to determine itsantimicrobial efficacy. The pH of the composition was 3.0. Table 3details the results of the efficacy trials of Sample B over 2 minutes. Asample with 20.0 wt. % ethanol, 0.62 wt. % non-ionic surfactant, 1.50wt. % enhancer, 1.50 wt. % organic acid, 0.20 wt. % chelating agent, andthe balance water (“Sample C”) was tested according to the methodsdescribed above to determine its antimicrobial efficacy. The pH ofSample C was 4.00. Table 3 details the results of the efficacy trials ofSample D over 90 seconds. A sample with 17.5 wt. % ethanol, 0.62 wt. %non-ionic surfactant, 0.75 wt. % enhancer, 0.6 wt. % organic acid, 0.25wt. % chelating agent, and the balance water (“Sample D”) was testedaccording to the methods described above to determine its antimicrobialefficacy. The pH of Sample D was 4.00. Table 3 details the results ofthe efficacy trials of Sample D over 90 seconds. These resultsdemonstrate rapid antimicrobial efficacy in as little as 15 seconds.

TABLE 3 Time (seconds) Average Percent Positive Sample A 0 100.00% 1516.67% 30 5.79% 60 5.26% 90 2.73% 120 1.67% Sample B 0 100.00% 15 70.00%30 15.00% 60 10.00% 90 2.50% 120 2.50% Sample C 0 100.00% 15 6.67% 301.67% 45 1.67% 60 1.67% 90 0.00% Sample D 0 100.00% 15 22.50% 30 2.50%45 2.50% 60 2.50% 90 0.83%

Example 4

The efficacy of individual ingredients compared to a full antimicrobialformulation was tested to demonstrate that the synergistic antimicrobialimprovement of the composition is more than just an additive effect.Specifically, five samples were prepared, as outlined below in Table 4,and tested against S. aureus at various contact times according to ASTME2783.

TABLE 4 Log Reductions (Log CFU/ml) Non-ionic 30 2 5 15 30 SampleEthanol surfactant Buffer Enhancer pH seconds minutes minutes minutesminutes A 18.0-22.0% — — — 4.01 −0.03 <1.25 <1.25 3.50 >5.72 B —0.65-0.8% — — 4.02 0.09 <1.25 <1.25 <1.25 <1.25 C — — — 0.1-0.4% 3.91−0.10 <1.25 <1.25 <1.25 <1.25 D — — 1.0-1.5% — 4.01 −0.15 <1.25 <1.25<1.25 <1.25 E 18.0-22.0% 0.65-0.8% 1.0-1.5% 0.1-0.4% 4.00 >4.45 — — — —

As illustrated above in Table 4 and accompanying FIG. 1, at individualconcentrations of about 18.0-22.0 wt. % ethanol, 0.65-0.8 wt. %non-ionic surfactant, 1.0-1.5 wt. % buffer, and 0.1-0.4 wt. % enhancer,none of the ingredients exhibited antimicrobial efficacy against S.aureus at a pH of about 4.0. (See Samples A, B, C, and D). In contrast,Sample E includes each component combined at the same concentrationlevels outlined in Sample A, B, C, and D, and demonstrated a significantincrease in antimicrobial efficacy. Particularly, Sample E exhibited alog reduction of over 4.45 CFU/ml at 30 seconds, which demonstrates thatthe synergistic effect of the combination of ingredients used herein isnot additive.

Example 5

The efficacy of individual ingredients at varied concentration levelswas then tested to demonstrate that even at increased concentrations,the individual ingredients still do not have antimicrobial efficacy.Specifically, nine samples were prepared, as outlined below in Table 5,and tested against S. aureus at a contact time of 30 seconds, accordingto ASTM E2783.

TABLE 5 Alkyl Monosodium Sodium Log Reductions Sample Ethanolpolyglucoside Citrate Benzoate pH (Log CFU/ml) F — — 1.0-3.0% — 4.000.20 G — — 5.0-7.0% — 4.00 0.31 H — — 9.0-11.0%  — 3.99 0.22 I — — —0.5-1.5% 4.01 0.41 J — 0.5-1.5% — — 4.03 0.53 K — 4.0-6.0% — — 4.02 0.63L — 9.0-11.0%  — — 4.00 0.59

As illustrated above in Table 5 and accompanying FIG. 2, even when theindividual concentrations of the non-ionic surfactant (alkylpolyglucoside) and buffer (monosodium citrate) were increased toindividual concentrations of 9.0-11.0 wt. %, the compositions did notshow antimicrobial efficacy. Thus, this further supports that it is thesynergistic combination of the ingredients that provides the unexpectedincrease in antimicrobial efficacy.

Example 6

The efficacy of the antimicrobial composition was tested against S.aureus 6538 at a contact time of 90 seconds, based on the AOAC 961.02test method, modified for towelettes. Three different groups ofcompositions were tested: Group A includes a comparative sampleincluding only ethanol and a non-ionic surfactant; Group B comprises aninventive composition that included ethanol, a non-ionic surfactant, abuffer, and an enhancer; and Group C comprises a second inventivecomposition that included ethanol, a non-ionic surfactant, a buffer, anenhancer, and a chelating agent. For each composition group, the ethanollevels were varied to demonstrate that it is not ethanol alone causingthe reduction in S. aureus.

TABLE 6 Formula Non-ionic Chelating Percent of Number Ethanol surfactantBuffer Enhancer agent pH Carriers Positive A-1 40% 0.65-0.8% — — — 3.0018%  A-2 30% 0.65-0.8% — — — 3.03 62%  A-3 20% 0.65-0.8% — — — 2.99100%  A-4 10% 0.65-0.8% — — — 2.99 100%  B-1 50% 0.4-0.65% 0.5-0.8%0.3-0.6% — 4.00 0% B-2 45% 0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 5% B-3 40%0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 1% B-4 35% 0.4-0.65% 0.5-0.8%0.3-0.6% — 4.00 9% B-5 30% 0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 3% B-6 25%0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 5% B-7 20% 0.4-0.65% 0.5-0.8%0.3-0.6% — 4.00 10%  B-8 15% 0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 15%  B-910% 0.4-0.65% 0.5-0.8% 0.3-0.6% — 4.00 30%  B-10  5% 0.4-0.65% 0.5-0.8%0.3-0.6% — 4.00 75%  C-1 50% 0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.402% C-2 45% 0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.40 0% C-3 40%0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.40 6% C-4 35% 0.65-0.8% 0.1-0.4%1.0-1.5% 0.5-0.25% 3.40 8% C-5 30% 0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25%3.40 16%  C-6 25% 0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.40 3% C-7 20%0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.40 13%  C-8 15% 0.65-0.8%0.1-0.4% 1.0-1.5% 0.5-0.25% 3.40 8% C-9 10% 0.65-0.8% 0.1-0.4% 1.0-1.5%0.5-0.25% 3.40 19%  C-10  5% 0.65-0.8% 0.1-0.4% 1.0-1.5% 0.5-0.25% 3.4055% 

As shown above in Table 6 and illustrated in FIG. 3, Comparative ExampleGroup A (ethanol+surfactant) did not achieve an efficacy of less than15% of carriers positive, even at ethanol levels upwards of 40%. Atethanol levels of 10-20%, there was growth of S. aureus from allcarriers. In contrast, Group B formulations (comprisingethanol+surfactant+a buffer+an enhancer) demonstrated efficacy startingat 10% ethanol and achieved 10% or lower carriers with growth at ethanollevels at 20% or above. Group C formulations (comprisingethanol+surfactant+a buffer+an enhancer) also demonstrated high efficacyat the low ethanol levels, with the percent positive carriers being lessthan 15% starting at 15% ethanol concentration. Thus, the efficacy ofthe formulation is improved by the addition of at least two of asurfactant, enhancer, and buffer.

Example 7

The efficacy of the antimicrobial composition comprising alcohol and twoor more of a non-ionic surfactant, enhancer, and a buffer was tested todetermine their effectiveness on hard, non-porous, inanimateenvironmental surfaces according to modified AOAC 961.02 method.Formulations were sprayed onto glass slides inoculated with S. aureusand neutralized after 20 seconds of exposure to the formulation. Thereduction in S. aureus was then quantified and recorded.

As shown below in Table 7, Sample (a) includes each of ethanol, anon-ionic surfactant, a buffer, and an enhancer, at a low pH of 3.40,and achieves a very efficacious log reduction of 5.31 log CFU. Samples(b)-(d) demonstrate that one of the surfactant, buffer, or enhancer canbe removed while still maintaining efficacy.

TABLE 7 Non-ionic Log Reductions Composition Ethanol surfactant BufferEnhancer pH (Log CFU) (a) 22.0-27.0% 0.65-0.8% 1.0-1.5% 0.1-0.4% 3.405.31 (b) 22.0-27.0% 0.65-0.8% 1.0-1.5%   0.00% 3.40 5.62 (c) 22.0-27.0%0.65-0.8%   0.00% 0.1-0.4% 3.40 4.18 (d) 22.0-27.0%     0.00% 1.0-1.5%0.1-0.4% 3.40 4.02 (e)    0.00% 0.65-0.8% 1.0-1.5% 0.1-0.4% 3.40 3.41

Example 8

The efficacy of the antimicrobial composition comprising alcohol and twoor more of a non-ionic surfactant, enhancer, and a buffer was tested todetermine their effectiveness on hard, non-porous, inanimateenvironmental surfaces according to modified AOAC 961.02 method.Formulations were sprayed onto glass slides inoculated with S. aureusand neutralized after 20 seconds of exposure to the formulation. Thereduction in S. aureus was then quantified and recorded.

Table 8, below, demonstrates that there is no loss in efficacy wheningredients in the same category are substituted within the formulation.For instance, in Composition b, salicylic acid was substituted forsodium benzoate (Composition a) as an enhancer. Each compositionmaintained sufficient efficacy with log reductions of at least 4 logCFU. The same maintenance in efficacy is found in Compositions c and b,wherein sodium lauryl sulfate was substituted for caprylyl/caprylglucoside. Compositions e-f include various surfactants that alldemonstrate sufficient efficacy when included in the inventivecomposition.

TABLE 8 Caprylyl/ Sodium Mono Log Capryl lauryl Undeceth- TridecethCaprylyl Laureth Sodium Glutaric Sodium Salicylic Reductions Comp.Ethanol Glucoside sulfate 5 9 Glucoside 7 Citrate Acid Benzoate Acid pH(Log CFU) a 20.00 0.71 — — — — — 1.28 — 0.33 — 3.40 4.75 b 20.00 0.71 —— — — — 1.28 — — 0.33 3.40 5.17 c 20.00 0.71 — — — — — — 1.28 0.33 —3.40 4.96 d 20.00 — 0.71 — — — — 1.28 0.33 — 3.40 5.57 e 20.00 — — — —0.71 — — 1.28 0.33 — 3.40 4.15 f 20.00 — — 0.71 — — — — 1.28 0.33 — 3.405.29 g 20.00 — — — 0.71 — — — 1.28 0.33 — 3.40 5.45 h 20.00 — — — — —0.71 — 1.28 0.33 — 3.40 5.61

Although exemplary embodiments have been described herein, it should beappreciated that many modifications can be made without departing fromthe spirit and scope of the general inventive concepts. All suchmodifications are intended to be included within the scope of theexemplary embodiments disclosed herein, which is to be limited only bythe following claims.

What is claimed is:
 1. An antimicrobial composition comprising: fromgreater than 15 to less than 40 wt. % of one or more C₁₋₈ alcohols; oneor more surfactants; one or more enhancers; and one or more buffers,wherein the total concentration of the enhancers and the bufferscollectively is from greater than 0.75 to 3 wt. %, wherein the pH of theantimicrobial composition is less than 5, and wherein each wt. % isbased upon the total weight of the antimicrobial composition.
 2. Theantimicrobial composition of claim 1, wherein the composition is devoidof auxiliary antimicrobial agents.
 3. The antimicrobial composition ofclaim 1, wherein the pH of the antimicrobial composition from 3 to lessthan
 5. 4. The antimicrobial composition of claim 1, wherein thecomposition comprises from greater than 20 to less than 35 wt. % of theone or more C₁₋₈ alcohols, based upon the total weight of theantimicrobial composition.
 5. The antimicrobial composition of claim 1,wherein the composition comprises from 0.05 to 15 wt. % of the one ormore surfactants, based upon the total weight of the antimicrobialcomposition.
 6. The antimicrobial composition of claim 1, wherein thesurfactants comprise one or more amphoteric surfactants.
 7. Theantimicrobial composition of claim 6, wherein the surfactants compriseone or more amine oxide surfactants.
 8. The antimicrobial composition ofclaim 7, wherein the amine oxide surfactants comprise lauramine oxide.9. The antimicrobial composition of claim 6, wherein the surfactantscomprise one or more betaine surfactants.
 10. The antimicrobialcomposition of claim 9, wherein the betaine surfactants comprisecocamidopropyl betaine.
 11. The antimicrobial composition of claim 1,wherein the one or more buffers comprise one or more organic acids,salts of organic acids, or combinations thereof.
 12. The antimicrobialcomposition of claim 11, wherein the one or more buffers comprise citricacid, lactic acid, formic acid, acetic acid, propionic acid, butyricacid, caproic acid, oxalic acid, maleic acid, benzoic acid, malic acid,valeric acid, carbonic acid, uric acid, the salts thereof, orcombinations thereof.
 13. The antimicrobial composition of claim 1,wherein the composition comprises from 0.4 to 2.5 wt. % of the one ormore buffers, based upon the total weight of the antimicrobialcomposition.
 14. The antimicrobial composition of claim 1, wherein oneor more enhancers comprise one or more of sorbic acid, sorbatecompounds, benzoic acid, benzoate compounds, sulphur dioxide, sulphitecompounds, natamycin, nitrate, nitrate compounds, salicylic acid,phenoxyethanol, thymol, cinnamaldehyde, methylparaben, propylparaben,sodium xylene sulfonate, 1,2 octane diol, 1,2 decane diol, the saltsthereof, or combinations thereof.
 15. The antimicrobial composition ofclaim 1, wherein the composition comprises from 0.01 to 3 wt. % of theone or more enhancers, based upon the total weight of the antimicrobialcomposition.
 16. The antimicrobial composition of claim 1, wherein thetotal concentration of the buffer and the enhancer collectively is from1 to 3 wt. %.
 17. The antimicrobial composition of claim 1, wherein thecomposition further comprises from 0.001 to 2.0 wt. % of one or morechelating agents, based upon the total weight of the antimicrobialcomposition.
 18. The antimicrobial composition of claim 1, wherein: theone or more buffers comprise one or more organic acids; and the one ormore enhancers comprise one or more salts of aromatic acids.
 19. Theantimicrobial composition of claim 1, wherein the composition is devoidof peroxide.
 20. The antimicrobial composition of claim 1, wherein theantimicrobial composition consists of: the one or more C₁₋₈ alcohols;the one or more surfactants; the one or more enhancers; the one or morebuffers; and optionally water.
 21. An antimicrobial compositioncomprising: from greater than 20 to less than 40 wt. % of one or moreC₁₋₈ alcohols; one or more surfactants, wherein the one or moresurfactants consist of amphoteric surfactants; one or more enhancers;and one or more buffers; wherein the pH of the antimicrobial compositionis less than 5, and wherein each wt. % is based upon the total weight ofthe antimicrobial composition.
 22. An antimicrobial compositioncomprising: from greater than 20 to less than 40 wt. % of one or moreC₁₋₈ alcohols; one or more surfactants; one or more enhancers; and from0.1 to 3 wt. % of one or more buffers, wherein the composition is devoidof auxiliary antimicrobial agents, wherein the pH of the antimicrobialcomposition is less than 5, and wherein each wt. % is based upon thetotal weight of the antimicrobial composition.
 23. An antimicrobialcomposition comprising: from greater than 25 to less than 40 wt. % ofone or more C₁₋₈ alcohols; from 0.5 to 15 wt. % of two or moreamphoteric surfactants; one or more enhancers; and one or more buffers,wherein the total concentration of the enhancers and the bufferscollectively is from greater than 0.75 to 3 wt. %, wherein the pH of theantimicrobial composition is less than 5, and wherein each wt. % isbased upon the total weight of the antimicrobial composition.
 24. Theantimicrobial composition of claim 23, wherein the surfactants compriseone or more amine oxide surfactants and one or more betaine surfactants.25. The antimicrobial composition of claim 24, wherein the amine oxidesurfactants comprise lauramine oxide.
 26. The antimicrobial compositionof claim 24, wherein the betaine surfactants comprise cocamidopropylbetaine.